Study on the Formation and Decomposition of the Amadori Compound N-(1-Deoxy-D-Fructos-1-yl)-Glycine in Maillard Model Systems

Summary The formation and degradation of N-(1-deoxy-D-fructos-1-y1)-glycine (DFG) were studied in unbuffered aqueous solutions at 90°C over a period of 2 hours. The pH was kept constant at 6 or 7 during the reaction. Both the formation and decomposition of DFG was faster at pH 7 than at pH 6. Yields of DFG were 13 mol% after a reaction period of 2h. Almost 60% of DFG was degraded at pH 7 after 1 h, whereas 55% was still unreacted at pH 6 after 2 h of heating. 4-Hydroxy-2,5-dimethyl-3(2H)-furanone (furaneol) was the most flavour-active compound generated. After 2 h of reaction, DFG yielded 110 and 190 mg/mol furaneol at pH 6 and 7, respectively. The reaction of glucose and glycine resulted in 2 and 27 mg furaneol per mol glucose at pH 6 and 7, respectively. These results indicate that furaneol is preferably generated from DFG under conditions favouring 2,3-enolization.